/Engine/Plugins/Runtime/Metasound/Source/MetasoundFrontend/Public/MetasoundFrontendController.h
Finds a variable inspecting the nodes associated with the variable.
If found, returns valid variable handle. An invalid handle otherwise.
[FVariableHandle](API\Plugins\MetasoundFrontend\FVariableHandle) FindVariableContainingNode ( const [FGuid](API\Runtime\Core\Misc\FGuid) & InNodeID )